[quote=@Dannyrulx]
<Snipped quote by Pudding>

It's the 'we killed tons of natives, let's stuff ourselves to bursting' holiday I think.
[/quote]

Maybe in the ye olden days. Nowadays, its simply the "Let's have big awkward family meetings and pretend like we know each other even though we literally only see ourselves occasionally on this holiday. Also: Food" 

Source:

IMA MURCICAN! *Frantically Waves flag while a fleet of bald eagles fly over, also carrying american flags*